The above profile, provided by Lawrence, shows the profile of the first 30Km of the 2004 Etape du Tour - yes the section where you are expected to average 30kph.

Don’t be alarmed - it is not as severe as it looks! The maximum slope is around 4% on two separate 1Km stretches, but elsewhere the gradient is no more than 2% or 3%.  The average rise over the first 12 km is a mere 125 meters. Its not flat though!